No. 116 

1961 

FURTHER OBSERVATIONS OF SNOW AND 

FROST IN THE ADIRONDACKS 

Snow-depth and water-content measurements were made 

in March and April 1960 in the vicinity of Paul Smiths, New 

York, to check on procedures developed the previous year for 

predicting snow accumulation and melt. 

Eight 200-foot snow courses were laid out, two each 

in the four hardwood and conifer cover type conditions previously studied, but in different stands. Snow measurements 

were taken at 20-foot intervals along the courses at the 

time of maximum accumulation (March 21) and at the minimum 

accumulation with complete snow cover (April 18). Canopy 

closure over each sampling point was measured with a densiometer. 

The percentage of canopy closure for each snow course 

was then used to estimate the snow-water content ratio 

(depth in forest condition/depth in hardwood saplings) for 

the time of maximum snow accumulation, employing the regression developed from the 1959 data. The estimated ratio was 

then multiplied by 8.6 inches, the average snow-water content of the two hardwood-sapling courses, to estimate the 

snow-water content of the three other forest conditions 

(table 1). Percentage of canopy closure for each snow course 

was also used to estimate the snow-melt in inches per degree 

-day above 32'~.; and the actual and predicted melt during 

the period March 21 to April 18 were calculated (table 1). 

Average maximum snow-water accumulation for the four 

cover conditions was 8.15 inches; in 1959 it was 7.96 inches. 

The 1960 melt-season had 137 degree-days between maximum and 

minimum accumulations; the 1959-season had 118. 

l~oward W. Lull and Francis M. Rushmore. Snow accumulation and melt under 

certain forest conditions in the Adirondacks. U. S. Forest Serv. Northeast. 

Forest Expt. Sta., Sta. Paper 138. 16 pp., illus., 1960. 
Conifer-Branch Interception 

For observing comparative snow interceptim by conifers, 4-foot long branches of balsam fir, red spruce, white 

pine, and hemlock were nailed to two posts at a height of 5 

feet, simulating two stems bearing branches of different 

species. Observations of snow depth, at three points on each 

branch, were made during the period December 8, 1959, to 

March 22, 1960. Miniature depth gages fastened at the measurement points made it possible to measure snow depth without disturbing the snow. 

Table 1.--Snow accumulation and melt, based on 

Dercentaee of cano~v closure 

Table 2.--Snow accumulation on conifer branches 

Cover type 

Table 3.--Changes in snow depth on branches during periods of snow loss, 

in inches 

Percent Inches Inches Inches Inches 

Conifer saplings 66 7.5 7.4 0.043 0.036 

60 7.7 7.8 .046 .035 

Conifer sawtimber 60 7.7 7.8 .046 .044 

64 7.6 8.0 .044 .044 

Hardwood saplings 2 8 -- 8.0 .062 .053 

2 4 - - 9.2 .064 .054 

Hardwood sawtlmber 2 3 8.9 8.6 .065 .061 

20 8.9 8.4 .066 .060 

Species 

Balsam fir 

Red spruce 

White pine 

Hemlock 

Canopy 

closure 

Melt per 

degree-day 

above 32O F. 

Predicted 

Maximum 

snow-water 

accumulation 

Frequency 

of 

occurrence 

Red 

spruce 

Predicted Actual 

Post 

mean 

Dec. 10 - Dec. 14 Sun bright, light 3.2 3.6 2.4 4.2 

wind, followed by .7 .7 .8 .9 

rainfall 

Dec.31-Jan.7 Strongandgusty 3.9 3.7 2.7 3.0 

winds .4 1.4 .3 .7 

Jan. 20 - Jan. 26 Light snow and 6.2 4.2 4.0 3.7 

moderate wind 3.7 3.0 .2 4.3 

Jan. 28 - Jan. 29 Strong wlnd and 5.5 4.3 2.1 2.6 

snow mixed with 1.1 1.1 .6 1.1 

rain 

Balsam 

fir 

Snow-loss 

periods 

Actual 

Post 1 

Percent 

2.13 84 

1.84 76 

1.78 69 

1.18 63 

Inches 

2.08 2.28 2.72 2.36 

1.49 1.90 1.82 1.74 

1.53 2.24 1.97 1.91 

1.30 1.48 1.38 1.39 

A 

Post 2 

Weather 

during period 

Inches 

2.22 2.12 1.36 1.90 

1.90 2.36 1.54 1.93 

1.25 1.96 1.72 1.64 

1.34 .83 .72 .96 

A 

White 

pine 

B C Mean B C Mean 
BALSAM FIR RED SPRUCE BALSAM FIR 

8 l NCHES 0 8. H. 4 l NCHES D. H 6 INCHES 4 INCHES 

0 48 120 4 812 0 4 81216 

LENGTH OF TRE NCH, IN FEET 

C] SNOW FROST 

Figure 1. --Typical snow and frost profiles under conifers. 

Snow was observed on the branches on 51 days. Adding 

18 week-end days on which snow was probably present gives a 

total of 69 snow-days during the 106-day period--or, snow 

was present on the canopy, in various amounts, for about 

two-thirds of this period. Needles remained on the cut 

branches all winter and stayed green. 

Maximum accumulations were 4.7 inches on balsam fir, 

4.3 inches on red spruce, 6.2 inches on white pine, and 4.5 

inches on hemlock. Average snow depth for each position 

measured, each post-species mean-, and frequencies of occurrence are shown in table 2 (positions A, B, and C were 

appro~imate~ly I$., 24, and 3& feet, respectively, from the 

posts). 

In an analysis of variance of the snow-depth data for 

species differences, only between hemlock and other species 

was snow-depth difference statistically significant. The 

least significant difference was 0.62. Differences between 

positions and between posts were not significant. 

For the 51 days of observation, frequency of snow occurrence on the branches ranged from 84 percent for balsam 

fir to 63 percent for hemlock. 

Differences in the rate at which snow disappeared 

from the branches during four snow-loss periods are illustrated in table 3, which gives snow depth at beginning and 

ending of the period. In three of the four periods, snow 

disappeared more rapidly from the hemlock and white pine 

branches than from the balsam fir and spruce. All three 

periods were marked by moderate to strong winds. During the 

mid-December period of light winds and bright sunshine, differences in loss rates were not so marked. 

The branches of hemlock are feathery and flexible, 

and they slope downward to form a poor platform for snow accumulation. Balsam fir had the best platform for snow support, apparently because needles persist along branches and 

there are many stiff branchlets. Spruce was next; and though 

its needles were small, like those of hemlock, the branch- 
lets were much stiffer and would not dump snow so readily. 

On a white pine branch, snow was caught within the bare 

whorls at two of the three positions measured, branches 

cupping the whorls permitting deepest accumulations of snow; 

the small stems provided good support for patches of snow 

when wind or thaws occurred. Time-lapse photographs of interception on white pine showed that snow accumulated on the 

needles, beginning at the bases of several needle fascicles, 

and later bending them over to form a platform. Patches of 

snow persisted longest where several branch tips, bent by 

snow, combined to form large platforms. 

Concrete Frost 

On March 21 and 24, 1960, about the time of maximum 

snow accumulation, observations were made at 160 points 

along the snow-survey courses to determine the presence and 

depth of concrete frost. Measurements were taken with a 

Stoeckeler and Thames frost probe.2 Frequency of occurrence 

and average depth of frost were as follows: 

Frequency Average depth 

(percent) ( inches) 

Conifer saplings 30 

Conifer sawtimber 15 

Hardwood saplings 40 

Hardwood sawtimber 15 

On April 18 no concrete frost was found on the courses. 

These figures substantiate earlier findings that concrete 

frost in the upland forest is sporadic in occurrence. 

Concrete frost tends to concentrate beneath conifer 

crowns in the snow-interception zone. This tendency, first 

observed during the 1959 field season, was investigated in 

1960 by digging trenches beneath the crowns of isolated conifers (three red spruce and seven balsam fir) in a hardwood 

stand, and taking snow-depth and frost measurements every 

2 or 3 feet along the trench. Typical snow and frost profiles are shown in figure 1. 

No relationship between frost and snow depth can be 

deduced from these limited observations, because the concrete frost observed developed from antecedent, unobserved 

weather and snow conditions. 

--HOWARD W. LULL and FRANCIS M. RUSHMORE* 

Northeastern Forest Experiment Station 

Forest Service, U.S. Dept. Agriculture 

L~. H. Stoeckeler and J. L. Thames. The Lake States penetrometer for meas- uring depth of soil freezing. Soil Sci. 85: 47-50, 1958. 

* Dr. Lull is Chief of the Northeastern Station's Division of Watershed 

Management Research. Mr. Rushmore is research forester in charge of the Northeastern Station's research center at Paul Smiths, N. Y., which the Station 

maintains in cooper ation with Paul Smith's College.